In a hard disk drive, a slider attaches a magnetic read/write sensor that reads and writes data on the disk to a suspension arm that moves the sensor to a desired track on the disk. The slider is configured to maintain the head at a stable flying height above the disk surface, creating a magnetic spacing as well as an air-bearing cushion resulting from the compression of air flow generated between the rotating disk and an air-bearing surface (ABS) of the slider facing the rotating disk.
The magnetic disk in the hard disk drive is where the magnetic data (bits) are stored in a form of magnetized and non-magnetized bits. The bits are stored in a soft magnetic material coated on the disk. On top of this magnetic material a very thin protective layer of diamond-like carbon (DLC) and a top lubricant layer for reducing friction and wear are provided. The DLC and lubricant layer protect the disk from corrosion and also prevent catastrophic failure due to slider disk contact.
As the physical spacing between the slider and the disk is reduced to achieve smaller magnetic spacing, the lubricant on the disk surface migrates to the slider body. Most of this lubricant flows from the leading edge towards the trailing edge of the slider due to the air shear force imparted by the air flow from the rotating disk. The lubricant accumulates at the trailing edge of the slider especially at the trailing edge face perpendicular to the air bearing surface. When the slider is unloaded or is non-operational, the accumulated lubricant can migrate back to the ABS surface in response to gravitational or other attractive forces. The migrating lubricant may coat the ABS where the read/write sensor is located, thereby providing an effectively increased magnetic spacing when the slider is loaded back on the rotating disk leading to a significant degradation in recording performance until the air shear force pushes the lubricant off of the ABS surface. With today's magnetic spacing being below 10 nm, a few Angstroms of lubricant film on the ABS can lead to a measurable loss of magnetic sensitivity.
The accumulated lube can also drop off of the slider and back onto the disk surface. This is commonly known as disk drive performance degradation caused by lubricant pick-up. The lubricant droplet can impact the slider stability as it flies over it and severe slider instability could lead to catastrophic head crash.
One solution that has been proposed to the lubricant pick-up problem is to retract the magnetic head to an area where circumferential speed is fastest when the hard disk drive is first powered on, such as to an outermost side of the flying guarantee area of the hard disk. The lubricant transferred from the disk to the slider can then be removed. However, it takes a long time (usually from seconds to minutes) to shear the lubricant off the trailing end of the slider, and remaining lubricant can again flow back onto the disk surface to undesirably increase the magnetic spacing and negatively affect the slider-disk interface.
Thus, what is needed is a slider for a hard disk drive which eliminates the problems associated with transferred lubricants. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background of the disclosure.